The present invention relates to a new therapeutic use of the lower alkanoyl L-carnitines and their pharmacologically acceptable salts to produce pharmaceutical compositions for the treatment of chronic intestinal disorders, in particular inflammatory bowel diseases, more particularly, ulcerative colitis or celiac disease.
The present invention also relates to pharmaceutical compositions suitable for rectal administration, particularly in the form of foams or enemas, containing the above-mentioned alkanoyl L-carnitines.
Ulcerative colitis is an inflammatory, ulcerative disease of the colon of unknown aetiology, very often characterised by haematic diarrhoea.
It usually originates in the recto-sigmoid area, from which it may spread proximally with possible involvement of the entire colon. Alternatively, it may attack a substantial portion of the large bowel right from the outset.
The complications of ulcerative colitis are particularly severe: it has been documented, in fact, that there is an enormous increase in the risk of colon cancer in patients suffering from ulcerative colitis. The incidence of colon cancer increases with both involvement of the entire colon and with a duration of disease exceeding 10 years.
In both the mild-to-moderate forms and the moderately or distinctly severe forms of the disease, corticosteroids constitute the drugs of choice, namely hydrocortisone, betamethasone and prednisone.
In the mild-to-moderate forms, physiological solution containing hydrocortisone is administered via an enema which is retained in the bowel as long as possible.
In the moderately severe forms, systemic corticosteroid therapy is necessary, consisting generally in 10-15 mg of prednisone t.i.d. or q.i.d. per os, which is capable of inducing drastic remission.
In the more severe forms requiring admission to hospital, the corticosteroid therapy is administered parenterally.
Both the systemic and topical administration of these drugs gives rise to serious side effects, mainly related to interference with the hypothalamo-pituitary-adrenal axis.
The side effects due to topical treatment of ulcerative colitis with these traditional corticosteroids are, far instance, transient or prolonged depression of adrenocortical function, weight gain, acne and moon face.
Though it is well known, particularly in the moderately severe forms of the disease, that the daily corticosteroid dose can be gradually reduced to 10-20 mg per week after 1-2 weeks of treatment, even such low corticosteroid doses continue to induce harmful side effects, the elimination or at least the drastic reduction of which constitutes a therapeutic goal of primary importance.
Celiac disease (or celiac syndrome) is a chronic intestinal disorder caused by a specific intolerance to gluten present in wheat, rye, barley and oats proteins included in the diet leading to dramatic changes in the small intestinal mucosa and subsequent impaired absorption. The celiac syndrome can affect genetically susceptible subjects (around 3‰). Symptoms comprise diarrhoea and other malabsorption symptoms, including total atrophy of intestinal mucosa.
It is known that in humans said pathologic alterations are produced by the action on the intestinal mucosa of digestion products of wheat gluten and, in particular, by the 70% ethanol soluble gluten protein fraction. Said protein fraction, generally name as xe2x80x9cprolaminxe2x80x9d (in wheat, in particular, it is named as xe2x80x9cgliadinxe2x80x9d), is present in several cereals in different proportions and is composed of numerous proteins with different molecular weights, and having an high glutamine (one glutamine residue every three amino acids) and proline (a proline residue every seven amino acids) content, and a low ionic strength (due to few residues able to ionise in solution).
Current treatment is effected by a well balanced gluten-gliadin-free diet high in calories and proteins and normal in fat. This excludes cereal grains with the exception of rice and corn. Patients affected by celiac disease not responding to gluten-gliadin-free diet are treated with glucocorticoid steroids. For example U.S. Pat. No. 4,958,418, assigned to Glaxo Group Limited, teaches the use of fluticasone dipropionate, an anti-inflammatory steroid, This patent clearly establishes that celiac disease, ulcerative colitis and Crohn""s disease are all embedded in the category of bowel diseases which respond to treatment of glucocorticoid steroids.
Based on the study of toxic peptides obtained by different prolamins, WO 97/27217, in the name of Istituto Superiore di Sanita, provides a protein compound having a sequence comprised in the proteins of durum wheat and being not toxic for celiac subjects, in particular a protein of the following sequence: QQPQDAVQPF.
WO 99/56698, in the name of Copenhagen University, discloses a method for treating celiac disease comprising interfering with the deamidation of at least one glutamine residue in a gliadin molecule. Practically, the treatment comprises administering to a patient suffering from celiac syndrome at least one of the following substances: a) a substance capable of increasing the pH in the gastroduodenal tract, e.g. an antacid, an anticholinergic agent, H2-receptor antagonists or a proton pump inhibitor, b) an antibiotic or antimicrobial agent acting against deamidating bacteria and/or a substance capable of interfering with deamidating enzymes. In a wide sense, a method for treating celiac disease is prospected in JP 1156927, to University Leland Stanford, by administering an antagonist to IFN-65.
There is still a strong need to make available a method for the treatment of celiac disease using a simple therapeutic scheme, with an easily managed drugs, with low or null side effects. The cost of the drug is also important.
Celiac patients, children in particular, proved to have low serum L-carnitine levels, most likely due to the damaged bowel mucosa (Lerner A. et al., Gut; 34: 933-935; Ceccarelli M. et al. Minerva Pediatr. 1992; 44:401-5). Indeed, celiac patients do, not absorb hexogenous L-carnitine. From a clinical point of view, L-carnitine deficiency cannot be associated to celiac disease. To date, it has never been demonstrated that L-carnitine deficiency may give celiac disease.
Therefore, it was totally unexpected to find that an alkanoyl L-carnitine is effective in the treatment of celiac disease according to is the teaching of the present invention. The object of the present invention is to provide a method for treating and pharmaceutical compositions useful for the treatment of chronic intestinal disorders, in particular inflammatory bowel diseases, more particularly, ulcerative colitis or celiac disease. The aim of the present invention is to provide compositions and methods for the treatment of the above disease, which, while affording equivalent therapeutic benefit, make it possible to use a lower daily dose of corticosteroid drug, with a consequent distinct reduction in the side effects induced by such drugs.
A further object of the present invention is to provide a composition of the above-mentioned type which enables complete remission of symptoms to be achieved and which lends itself to oral or, if necessary, to rectal administration, in the form of a foam or enema, thus making it possible to avoid corticosteroid administration via the parenteral route even in the most severe cases.
These objects are achieved according to the present invention by means of the use of lower alkanoyl L-carnitines in which the alkanoyl group, straight or branched, has 2-6 carbon atoms and of their pharmacologically acceptable salts to produce the aforementioned compositions. The preferred alkanoyl L-carnitines are acetyl, propionyl, butyryl, isabutyryl, valeryl and isovaleryl L-carnitine. Propionyl L-carnitine, butyryl L-carnitine and their pharmacologically acceptable salts are particularly preferred.
What is meant by a pharmacologically acceptable salt of an alkanoyl L-carnitine is any salt of the latter with an acid which does not give rise to unwanted toxic or side effects. These acids are well known to pharmacologists and pharmacy experts.
Non-limiting examples of such salts are, for instance, chloride, bromide, orotate, acid aspartate, acid citrate, acid phosphate, fumarate and acid fumarate, lactate, maleate and acid maleate, acid oxalate, acid sulphate, glucose phosphate, tartrate and acid tartrate.
Though, according to the present invention, the alkanoyl L-carnitine and the reduced dose of corticosteroid can be administered orally, it might be necessary that the preferred alkanoyl L-carnitine administration route is rectal. In particular, those forms of rectal administration, such as foams and enemas, are preferred, which allow prolonged contact between the alkanoyl L-carnitine and the intestinal tract affected by the inflammatory ulcerative disease.
The preparation of these foams and enemas and the choice of appropriate vehicles and excipients are well known to pharmacy experts.
These compositions capable of being administered by the rectal route may contain additional active ingredients such as anti-diarrhoea agents, antibiotics, anaesthetics, stool softeners and lubricants.
For example, an enema composition comprises from approximately 3 to approximately 15 grams, preferably 6-12 grams, of alkanoyl L-carnitine and possibly 400-600 mg of hydrocortisone or 20-50 mg of prednisone per litre of physiological solution.
Though the daily dose will depend, according to the judgement of the primary care physician, on the subjects weight, age and general condition, it is generally advisable to administer 1-4 g/dayxe2x80x94preferably 2-3 g/dayxe2x80x94of alkanoyl L-carnitine or a stoichiometrically equivalent amount of one of its pharmacologically acceptable salts. In the preferred rectal administration form, an enema of 500 mL physiological solution containing 5-10 g of alkanoyl L-carnitinexe2x80x94e.g. 6 g of propionyl L-carnitinexe2x80x94is administered twice daily.
Larger doses can safely be administered in view of the substantial non-toxicity of the alkanoyl L-carnitines.
In the embodiment relating to the treatment of celiac disease, the alkanoyl L-carnitine, among which propionyl L-carnitine is preferred, may be used alone or in combination with at least one active agent used in the treatment of celiac disease. Active agents for the treatment of celiac disease are well-known in the art and the skilled person will be able to determine the suitable agent. Glucocorticoids, such as hydrocortisone, prednisone or prednisolone may be used as well as other active agents. Preferably, the method according to the present invention is associated with the proper gluten-free diet.
In a further embodiment of the invention, the alkanoyl L-carnitines, and in the particularly preferred embodiment, propionyl L-carnitine, are combined with short chain fatty acids. The latter are used in celiac disease therapy. It is important that the alkanoyl L-carnitine and the short chain fatty acid be combined in a physical form and not bound in a chemical entity (such as, for example an ester). Though the inventors do not wish to be bound to any theory, it is believed that alkanoyl L-carnitines exert a protective effect toward the cells against potential damaging effects of short chain fatty acids.
In a still further embodiment of the invention, the alkanoyl L-carnitines, and in the particularly preferred embodiment, propionyl L-carnitine, are combined with amino acids, preferably glutamine. The latter are used in celiac disease therapy, where they exert a protective effect towards intestinal epitelial cells.
Details are given here below of clinical studies demonstrating the activity of the compounds according to the invention.